In another thread, @boatgeek asked about the weight penalty of papering fins with label paper. Here is a breakdown.
Conclusion: for balsa fins especially, the weight penalty for papering this way is quite steep, although I can't say how it compares to other methods. For this reason it is important to include some sort of estimate of this additional weight in your sim models, it really can make a difference in CG location.
If anyone wants to fill in this sort of information for their own preferred papering technique that would be great. Any method that includes significant amount of glue requires weighting a bare fin and then a fully papered fin to see the additional weight of paper, which should be relatively constant per unit area regardless of the fin thickness or material.
- My Avery label paper weighs 0.003 oz/in^2. Because you need to paper both sides of the fin (unless you're really weird ), that comes out to 0.006 oz of paper per square inch of fin. Note that this includes the "glue". In my case I only lightly CA the edges, which I deem to be negligible in this calculation. If you soak the whole fin with CA after papering then you'll need to factor that in.
- Balsa density varies enormously, but let's say that typical medium-density stock runs 0.1 oz/in^3.
- Let's say typical basswood density (also quite variable) is 0.3 oz/in^3
Fin material and thickness | Fin weight / in^2 (oz) | Label Paper weight / in^2 (oz) | Paper weight penalty |
1/16" balsa | 0.0062 | 0.006 | 97% |
3/32" balsa | 0.0094 | 0.006 | 64% |
1/8" balsa | 0.0125 | 0.006 | 48% |
1/16" basswood | 0.019 | 0.006 | 32% |
3/32" basswood | 0.028 | 0.006 | 21% |
1/8" basswood | 0.038 | .006 | 16% |
Conclusion: for balsa fins especially, the weight penalty for papering this way is quite steep, although I can't say how it compares to other methods. For this reason it is important to include some sort of estimate of this additional weight in your sim models, it really can make a difference in CG location.
If anyone wants to fill in this sort of information for their own preferred papering technique that would be great. Any method that includes significant amount of glue requires weighting a bare fin and then a fully papered fin to see the additional weight of paper, which should be relatively constant per unit area regardless of the fin thickness or material.
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